Transaction re-execution fails without authenticator and basic auth

[PhilippGackstatter]

Re-execution of transaction fails on v0.12.2 when basic authentication is used:

#[tokio::test]
async fn reexecution_fails() -> anyhow::Result<()> {
    let mut builder = MockChain::builder();
    let account = builder.add_existing_mock_account(Auth::BasicAuth)?;
    let note = builder.add_p2id_note(
        ACCOUNT_ID_SENDER.try_into()?,
        account.id(),
        &[FungibleAsset::mock(3)],
        NoteType::Public,
    )?;
    let chain = builder.build()?;

    let tx = chain
        .build_tx_context(account.id(), &[note.id()], &[])?
        .build()?
        .execute()
        .await?;

    let _reexecuted_tx = chain
        .build_tx_context(account.id(), &[note.id()], &[])?
        .authenticator(None)
        .tx_inputs(tx.tx_inputs().clone())
        .build()?
        .execute()
        .await?;

    Ok(())
}

The _reexecuted_tx line fails with:

Error: failed to respond to signature requested since no authenticator is assigned to the host

The signature generated by the authenticator should be added to the tx inputs after execution, and so providing an authenticator should not be necessary (here passing None) when passing in the tx inputs from the already executed tx.

[bobbinth]

Closed by #2099.